Traffic hit when traffic switches from stdby uplink to active uplink

[rajala]

I have a active-stdby uplink configuration. The uplink interfaces are connected to a different leaf switches in the fabric without lag/mlag configuration. Initially, traffic is routed through active uplink interface. I shutdown the leaf interface connected to the active uplink and traffic switched to stdby uplink as expected without any ping packet loss. However, when I did no shutdown on the leaf interface connected to the active uplink I observed traffic hit for quite sometime. Is this an expected behavior or known issue?

[Sreec]

So you have a leaf spine design in the network ?  Can you also confirm STP configuration and port status ( server facing ports ) before the switch over ?